Carrageenans are polysaccharides obtained from the red algae commonly known as seaweed. They are a structural component of seaweed and are extracted as three main types, namely iota, kappa and lambda, although there are other types as well, including kappa-II, mu and nu carrageenans. Carrageenans have been used extensively in the food, pharmaceutical and cosmetics industries as thickeners, gelling agent, and stabilizing and dispersing agents. Extensive pharmacological and toxicological studies have been conducted. Carrageenan has been found to be non-toxic by oral, dermal, and inhalation routes of administrations even at extremely high doses. The carrageenans were therefore classified as “generally recognized as safe” (GRAS) by the FDA in 19722. Further extensive oral pharmacokinetic studies conducted in pigs, rats, mice, gerbils, guinea pigs, ferrets, hamsters, dogs, and monkeys3-11 showed that the breakdown of the carrageenans in the gastrointestinal tract were minimal at best and that absorption was virtually non-existent
International Patent Publication WO 94/15624 teaches use of sulfated polysaccarides such as iota carrageenan, dextran sulfate, kappa carrageenan, lambda carrageenan, heparin mimetics, heparin sulfate, pentosan polysulfate, chondrotin sulfate, lentinan sulfate, curdlan sulfate, de-N-sulfated heparin and fucoidan, to inhibit cell-to-cell transmission of HIV and thus the sexual transmission of Acquired Immune Deficiency Syndrome (AIDS), as well as Chlamydia organism. This publication teaches that iota carrageenan is the most efficacious of the commercially available sulfated carrageenans in preventing HIV infection and in blocking Chlamydia infection in vitro and in vivo.